Recently, the proliferation of combinatorial libraries in high throughput synthesis and screening (HTS) programs have led to an ever increasing emphasis on automation. The ability to prepare and test a large number of compounds quickly can provide a competitive advantage. Thus, automated preparation and evaluation has become a key process in lead discovery.
The recent explosion in the number of compounds available for screening, and the expected increase in compounds with the development of automated chemical synthesis, has meant that a large number of pharmaceutical and other chemical companies are in need of automated weighing of such compounds. However, several difficulties have been encountered in attempts to provide a fast, efficient, and cost-effective solution to the problem of automatically weighing large numbers of small samples.
Proposed solutions which simply implement robotic methods to remove and replace samples from racks to facilitate weighing present significant problems. Robotic fingers have difficulty in grasping individual samples for removal from among an array of closely placed samples in a rack. Certain devices function only with flat bottom containers, which are more difficult to return to the rack after weighing. Misplacement during return may result in spilling of the sample contents, or breakage of one or more samples (possible leading to contamination of one or more samples).
A major difficulty unsolved by current devices is the lack of speed when weighing a large number of samples. Current devices generally employ a robotic sample transfer assembly, which retrieves a sample from an array, transfers the sample to a separate balance, and then returns the sample container to a particular position in a holder, such as a test tube rack. Although some such systems may have the ability to identify the particular sample, and associate the sample with the measurement taken to enable later data recordation and processing, systems currently employed require a large amount of inefficient and time-consuming movement. The sample must be plucked from an array, moved to the balance, isolated from the surrounding environment by closing a door of a chamber surrounding the balance, retrieved from the balance after opening the door of the chamber, moved back into position relative to the array, and returned to the sample's original position. Thus, having the balance a considerable distance from the actual sample position within an array leads to a great deal lost time in moving each sample to and from the balance.
Current devices also handle a relatively limited number of samples during each run. It would be advantageous to provide an automated system which is capable of handling a larger number of samples than those devices currently available.
Accordingly, it is one object of the present invention to provide an automated weighing system which handles a larger number of samples per run than currently available devices. It is also an object of the invention to accomplish weighing of a large number of samples in less time, and with increased accuracy, handling efficiency and reliability. Additionally, another object of the invention is to provide a weighing system allowing increased control of an automated weighing apparatus, and increased versatility in data collection, storage and transformation.
An additional object of the present invention is to provide an automated system for dispensing liquid which handles a larger number of samples per run than currently available devices. It is also an object of the invention to accomplish filling of a large number of sample containers in less time, and with increased handling efficiency and reliability.